I found something interesting. I previously thought that people who were using Superlube 21030 on their H2D were either ignorant of Bambulab’s 92003 recommendation or else just wanting to save money, since it is much less expensive. However, it now looks as though they were the smart ones and I was the ignorant one: 21030 is apparently the better choice with respect to metal wear on the H2D.
Grok analysis
They are not the same grease with different part numbers. 21030 is the one to put on the H2D lead screws. 92003 is the one Bambu named, and it is the worse fit for that job.
Both are NLGI 2, NSF H1, PTFE-fortified, and safe on plastic. The base oil is the whole difference.
| Super Lube 21030 | Super Lube 92003 | |
|---|---|---|
| Base oil | PAO synthetic hydrocarbon | Silicone |
| Thickener | Fumed silica | Silicone grease matrix |
| Solid additive | Syncolon PTFE | Syncolon PTFE |
| Base-oil viscosity | 69 cSt at 40 °C, 8 cSt at 100 °C | 5,000 cSt at 25 °C |
| Range | −45 °F to 450 °F | −40 °F to 500 °F |
| Dropping point | >550 °F | No melt |
| Load data | Four-ball weld 400 kg, Timken 40 lb, salt-spray pass | Not published; silicone is a weak boundary lubricant |
| Dielectric | Yes (643 V/mil) | Yes (400 V/mil), higher resistivity |
| Best contact | Steel on brass or steel | Plastic, rubber, O-rings |
| 3 oz tube | $10.99 | $18.49 |
On the H2D, grease goes only on the three Z lead screws. Those are steel threads sliding in a nut. A PAO film at 69 cSt is the right weight for that: it stays in the thread, carries the sliding load, and the PTFE handles the metal contact. 92003’s silicone oil is roughly two orders of magnitude heavier at room temperature, and silicone is a poor oil for steel-on-brass. Super Lube adds PTFE to 92003 specifically because plain silicone grease is weak on metal. It will not hurt the nut, and it is what the Bambu wiki lists, but it lubricates the screw worse and costs more.
That viscosity gap is why H2 owners who have run both prefer 21030 over Bambu’s 92003 recommendation. Lucas 10533 sits in between at about 230 cSt at 40 °C; 92003 is the outlier.
92003 is the better tube only if the part is rubber or plastic: O-rings, idler bushings, a plastic gear that must not see hydrocarbon oil. It is also the more inert dielectric grease. None of that is the H2D lead-screw job.
Neither belongs on the X guide rail or the Y/Z linear rods. Those take oil. Super Lube 52004 is the matching oil; grease there packs the carriages and picks up dust.
Brass: neither has an active-sulfur EP package, so neither etches yellow metal. 21030 is still the better brass-nut grease because the PAO film actually stays in the contact and it passes a 100-hour salt-spray test. 92003 seals moisture well and does not attack brass, but it does not lubricate the thread as well.
Nothing the H2D actually greases is a plastic that 21030 is incompatible with.
I had also thought maybe Bambulab advised in favor of 92003 because it is more plastic compatible, but I haven’t found evidence that 21030 is incompatible with any plastic it might contact on the lead screws. As a check against Grok’s analysis, if anyone knows differently, please post.
The difference in viscosity perhaps explains why my subjective impression of 92003 was performing a bit “stiff”, which is what lead me to order the BX300/F I discussed above.
There had also been a long thread on the forum where people discussed their H2 brass nuts getting stripped out:
but in their case, the grease took on a brass color from the metal fragments, not the gray/black that I’m observing. For some reason they even thought they were better off replacing their H2 brass nuts with 3D printed plastic nuts, which on its face seems pretty radical.